Question 2 of 10 What type of system allows matter and energy to enter and exit? O A. Connected OB. Open O C. Closed O D. Isolated

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

Amerry-go-round of radius r, shown in the figure, is rotating at constant angular speed. the friction in its bearings is so small that it can be ignored. a sandbag of mass m is dropped onto the merry-go-round, at a position designated by r. the sandbag does not slip or roll upon contact with the merry-go-round. how would you rank the following different combinations of m and r on the basis of the angular speed of the merry-go-round after the sandbag "sticks" to the merry-go-round from largest to smallest. a) m = 10kg, r = 0.25r b) m = 20kg, r = 0.25r c) m = 10kg, r = 0.50r d) m = 10kg, r = 1.0r e) m = 15kg, r = 0.75r f) m = 40kg, r = 0.25r

Two blocks of aluminum (specific heat c=0.22 cal/g celsius) with masses of 1000 g and 100 g are at a temperature of 70 c. which block has more thermal (internal) energy? explain why?